lexing of scan.l with pcc-built flex dumps core on amd64

Using flex built with pcc, to compile scan.l, produces a core dump.
This works OK on i386, or if using the system lex built with either gcc or clang.

Steps to reproduce:
First, build and install pcc on NetBSD (by default pcc is not installed); NetBSD src includes pcc as of 20120325, but using 20121229 gives the same result.

Then, the easiest track is to try to build NetBSD building tools with the just-compiled pcc, like with
$ sh build.sh -V HAVE_PCC=1 HOST_CC=pcc -V MKPCC=yes -V MKGCC=no -U tools
After a while, it breaks while recompiling pcc, at scan.l; it is using the just-built nblex... Segmentation fault

Another way to reach the same point is to build flex with pcc, install it (or passing LEX=/path/to/just/built/lex) and try to rebuild pcc

Description

Using flex built with pcc, to compile scan.l, produces a core dump.
This works OK on i386, or if using the system lex built with either gcc or clang.
Steps to reproduce:
First, build and install pcc on NetBSD (by default pcc is not installed); NetBSD src includes pcc as of 20120325, but using 20121229 gives the same result.
Then, the easiest track is to try to build NetBSD building tools with the just-compiled pcc, like with
$ sh build.sh -V HAVE_PCC=1 HOST_CC=pcc -V MKPCC=yes -V MKGCC=no -U tools
After a while, it breaks while recompiling pcc, at scan.l; it is using the just-built nblex... Segmentation fault
Another way to reach the same point is to build flex with pcc, install it (or passing LEX=/path/to/just/built/lex) and try to rebuild pcc